"There and back" in a single SWA cable?

[HDRW]

I've been thinking of setting up solar panels on the roof of my shed (the house roof faces the wrong way) and having batteries and an inverter inside the shed. Before the Part P police leap in, Yes, I know this is a special installation! But I want to plan how I'm going to do it before I get anywhere near submitting anything to Building Control...

There will be a supply to the shed for the usual purposes, and a supply from the inverter in the shed back to the house. Can I run them in the same SWA cable?

If so, can I use 3-core and have to- and from- Lives, and a single Neutral for both directions? Or would it need to be 4-core and have Live & Neutral in each direction?

Anyone done anything like this who can give advice on it?

Cheers,

Howard

 

[breezer]

I think you would be wasting your time and money, honestly i do.

how much power do you suppose you will get from the solar cells?

how much do you suppose the cells will cost

how much money do you suppose you will save

there was a post from a U.S. Trucker who wanted to power an electric shower via an inverter and solar panels, bearing in mind the shower he wanted was around 9kw, thats a heck of a lot of panels and inverters

 

[Pensdown]

...you will only get 6-8 years out of a 10 year battery and the replacement cost will be far in excess of any any savings.

Solar is great for heating water but at the moment thats about it.

 

[plugwash]

if you wan't the inverter supply seperate then i'd suggest going for 4 core.

another alternative would be to get the equipment nessacerry for paralell running with the grid.

 

[slippyr4]

and bear in mind that most invertors spit out a double-sqaure wave, not a sine wave. Which has the potential to cause problems with some equipment, particularly audio.

Also, bear in mind you can get 4, and even 5 core SWA. Don't forget you probably need an earth too.

 

[plugwash]

isn't the armor usually a sufficiant earth?

iirc 5 core SWA attracts a large premium so if you do need a supllementry earth then its probablly better to just run it along side a 4 core.

 

[HDRW]

if you wan't the inverter supply seperate then i'd suggest going for 4 core.

another alternative would be to get the equipment nessacerry for paralell running with the grid.

Yes, I did consider a grid-tie inverter, but they are horendously expensive (well over a £Grand for the size I'd want) and at the time I started looking at this the electricity companies would only pay the generation rate for electricity fed to the grid - about 1/20th of the cost of buying it! But I see that some of the suppliers will now pay back at the same rate as they sell, as long as you stay under 5kW of generating capacity. You either have to pay £100 for an outgoing meter to be fitted, or they estimate how much you've generated! (Yeah, right!)

The battery setup is Plan A, and I'll see how I get on with it. I may then go for a grid-tie inverter as Plan B, but the disadvantage of that is that there is no protection from power cuts - it shuts down if the grid goes off.

Cheers,

Howard

 

[breezer]

if you are worried about several K on an inverter, how much do you suppose the solar cells are going to cost?

 

[HDRW]

and bear in mind that most invertors spit out a double-sqaure wave, not a sine wave. Which has the potential to cause problems with some equipment, particularly audio.

Right, but I already have a pure-sine inverter!

Also, bear in mind you can get 4, and even 5 core SWA. Don't forget you probably need an earth too.

Yes, although 3-core seems to be easier to find at decent prices! I suppose thinking about it more carefully, I should have the circuits separate, if only so I can isolate them individually.
I was planning on using the armour as the Earth (checked the tables and it seems to be fine for that) - I may run a 16mm² Earth cable separately if the EFLI proves not to be good enough, but I am fairly confident it will be.

Cheers,

Howard

 

[HDRW]

if you are worried about several K on an inverter, how much do you suppose the solar cells are going to cost?

My target price is a maximum of £3.50 per Watt - you have to shop carefully but this is achievable. The reason I was against grid-tie inverters was that with the payment for generated electricity at almost nothing (0.5p/kWh) it made no sense to use the grid to "store" excess power and then buy it back at 20x the price overnight. Even the most inefficient charger/battery/inverter setup should be able to achieve at least 50% return of power stored, ten times as much as selling/buying it back from the grid!

That equation has changed a lot recently, but my battery scheme also allows charging batteries at Economy 7 rates so the solar collectors aren't the whole story.

It's also not all about money - I want to start being Green a bit beyond just using CFLs and turning off the TV rather than leaving it in Standby...

Cheers,

Howard

 

[breezer]

I am still curious as to how much the solar cells are going to cost or how much you think they are going to cost, reason is i have an idea and i wanted to know how much you found them for

 

[slippyr4]

Yes, although 3-core seems to be easier to find at decent prices!

http://tlc-direct.co.uk/Main_Index/Cable_Index/Armoured_SWA/index.html

4 core only 20% more than 3 core.

 

[plugwash]

3 and 4 core are both widely used and easilly availible at reasonable prices.

Its when you go to 5 core and above that the rareity premium kicks in.

btw TLC are not a reasonablly priced supplier of SWA.

 

[HDRW]

I am still curious as to how much the solar cells are going to cost or how much you think they are going to cost, reason is i have an idea and i wanted to know how much you found them for

If you look carefully you can find quite a selection at about £3.50 per Watt, but there are some cheaper ones from abroad - there's a US site charging US$3 per Watt, although there's the additions of shipping & VAT (and maybe Import Duty) they still work out that you can get a kilowatt for less than £3,000.

I understand that B&Q are going to be selling their own systems for solar and wind power soon, but their prices are likely to be 2 or 3 times as much.

Cheers,

Howard

 

[ebee]

look,
this north Korea thing has got me thinking.
I set off a nuclear deice.
Ignore the flak from Bush & Co.
Use it to generate loads on Electric.
Sell it.
Buy stuff.
Quids in.
Even buy some green electric back so I`m a friendly state.
Everybody wins.
Simple.